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Modernizing the Plastics Resin Identification Code

A revised ASTM International standard on the Resin Identification Code, which details the labeling system for post-consumer plastics, is designed to provide for a more effective use of the system.

Stakeholders across the recycling industry will gain a valuable assist from a newly revised ASTM International standard that helps manage the end of life of plastic materials. That assist comes from the work of Subommittee D20.95 on Recycled Plastics, part of ASTM Committee D20 on Plastics, which has recently completed enhancements to D7611/D7611M, Practice for Coding Plastic Manufactured Articles for Resin Identification. ASTM D7611, first issued in 2010, covers the Resin Identification Code, or RIC, system for identifying the various types of plastic resin used in manufactured articles. (See “Plastic Packaging Resins: A Closer Look,” below, for more about the resins used in plastic packaging.)

Better Recycling through Quality Control

The Resin Identification Code was developed by the Society of the Plastics Industry at the urging of recyclers during the 1980s. A growing number of communities around the United States were implementing recycling programs in an effort to stem rising waste generation. As a result, SPI launched the code in 1988 to meet the need for a uniform coding system to identify the resin content of products commonly found in the residential waste stream.

Plastics coding enables consumers, waste recovery facilities and other stakeholders to more properly sort articles prior to recycling. By facilitating this quality control sorting process, the RIC system drives more effective recycling efforts while also ensuring that the recycled plastic is as homogenous as possible. Since plastic is not limited to any one material, but rather a family of materials with varying properties, consistency in recycled plastic is critical to the requirements of the end users of recycled materials.

While the plastics industry has been successful in reducing the amount of waste generated, the need for more effective utilization of the RIC system to drive further improvement remains strong. According to the U.S. Environmental Protection Agency, 31 million tons (28 Tg) of plastic waste were generated in the United States in 2010, representing 12.4 percent of total municipal solid waste. EPA notes that the recycling rate for different types of plastics varies greatly. Overall, the plastics recycling rate was eight percent, or 2.4 million tons (2.2 Tg), during 2010. This recycling rate increases for specific plastics, particularly polyethylene terephthalate bottles and jars and high density polyethylene bottles, which were recycled at 29 and 28 percent, respectively, in 2010.1

The Path to a More Robust Coding System

SPI began working with ASTM International in 2008 to involve technical and industry stakeholders in updating and maintaining the RIC system to better address changing societal needs and advancements in plastics materials. The RIC system was first adopted as ASTM standard D7611/D7611M in 2010.

The latest revisions to D7611, published in June, modernize the RIC system, providing for more effective utilization across the stakeholder community. According to Melissa Hockstad, vice president of science, technology and regulatory affairs at SPI, Washington, D.C., the revised D7611 standard underscores the focus of Subcommittee D20.95 in updating the code to meet current and evolving industry practices.

“Diverse experts have come together in the open and transparent ASTM process to develop changes to D7611 that better align the RIC system with modern era requirements,” says Hockstad. “The recent efforts of Subcommittee D20.95 address several important technical issues that support the underlying focus of the code, enable the inclusion of new resins and lay the groundwork for future improvements.”

The major revision to ASTM D7611 is a change to the graphic marking symbol, which is used on the bottom of a plastic bottle or container to identify its resin type. The RIC system had used a “chasing arrows” symbol surrounding the number that defines the resin used in the product’s packaging. Under D7611, this marking symbol is now specified as a solid equilateral triangle around the number.

The use of the new symbol is aimed at increasing user understanding of the RIC system and its proper utilization. The system was originally developed and continues to be solely dedicated to identifying resin content rather than product recyclability. By replacing the chasing arrows graphic — commonly associated with recycling — with an equilateral triangle, ASTM D7611 helps bring focus back to the system’s core mission: resin identification and quality control prior to recycling.

Bridget Anderson, director, recycling unit, Bureau of Waste Prevention, Reuse and Recycling, New York City Department of Sanitation, N.Y., participated in revising the D7611 standard as a member of the responsible ASTM D20.95.01 task group. “Changing the marking symbol in D7611 decouples the RIC system from the recycling message, which has been a significant source of confusion by the public,” Anderson says. “This is an important first step to help ensure the long-term integrity and viability of the RIC system. Building on this effort, committee members can marshal their collective expertise to continue to create a more robust coding system that is relevant and useful to multiple stakeholders in the recycling system today and into the future.”

Tim Farnan, senior state program administrator for the Minnesota Pollution Control Agency, St. Paul, Minn., and also a member of the D20.95.01 task group, similarly views the changes to D7611 as an important step in the RIC code’s evolution. “This is a very positive development that not only helps to eliminate confusion surrounding the RIC system but hopefully will inspire manufacturers to better work with recyclers to further reduce waste generation," Farnan says. "Consumers, who are the most efficient and convenient sorters of plastics in the value chain, will also benefit from a more straightforward and understandable tool to support their role in recycling programs.”

Future Agenda: Addressing Innovations in Polymer Applications

As part of its ongoing efforts, the D20.95.01 task group is assessing how to differentiate between different melt flows — a common industry method for evaluating the fluidity of plastics — within each resin, identify certain additives that might significantly change the properties of a resin and better label individual resins that are currently designated as “other” in the current RIC system. One notable polymer application that the group is looking at is polylactic acid (PLA), an innovative resin derived from renewable resources such as cornstarch. Commercial use of PLA is increasing in applications such as loose-fill packaging, compost bags, food packaging and disposable tableware.

The task group is also discussing whether a new code is needed for linear low density polyethylene to enable products made from this technology to be accurately identified and distinguished from products marked as high density polyethylene (HDPE) or low density polyethylene (LDPE).

Thomas Pecorini, technology fellow, Eastman Chemical Co., Kingsport, Tenn., and chairman of the D20.95.01 task group, says, “Clearly and distinctly identifying new resins through the ASTM D7611 code system will support consumers, brand owners, retailers, waste collectors, municipal recovery facilities and reclaimers in identifying manufactured articles made from these materials and ultimately help to facilitate the desired recycling of these products.”

All parties interested in contributing to potential D7611 revisions are invited to join the ASTM task group responsible for the standard. For more information, contact D20 staff manager Alyson Fick, ASTM International (phone: 610-832-9710).

ASTM D7611 and its related adjunct are available for purchase at www.astm.org or by contacting ASTM Customer Relations (phone: 877-909-ASTM). The D7611 adjunct contains graphic representations of the Resin Identification Code as a molded, imprinted or raised symbol or wording and is available for download in PDF format.

Reference

1. U.S. Environmental Protection Agency, “Plastics.”

Doug Clauson is a freelance writer based in Wynnewood, Pa.

Through the use of the Resin Identification Code system, bottles and containers are marked with a numeral from one to seven corresponding to a type of plastic resin. ASTM D7611 currently provides codes for the six most commonly found resin types, with a seventh category created for all other types. These categories are: 1) polyethylene terephthalate (PETE or PET); 2) high density polyethylene (HDPE or PE-HD); polyvinyl chloride (V or PVC); 4) low density polyethylene (LDPE of PE-LD); 5) polypropylene (PP); 6) polystyrene (PS); and 7) other, including materials made with more than one resin from categories 1-6.

The category one resin, PETE, is used in plastic bottles for soft drinks, water, juice, beer and other beverages, as well as in jars for products such as peanut butter, jelly and pickles. PETE has numerous recycling uses; among them are fiber for carpets and fleece jackets, and containers for food and non-food items.

HDPE also is used in the manufacturing of bottles for milk, cosmetics, detergents and other products as well as for plastic bags used in grocery and retail stores. In addition to packaging, HDPE is used in industrial applications such as extruded pipe and for wire and cable covering. Among its diverse recycling applications are bottles for non-food items, plastic lumber for outdoor decking and plastic garden edging.

PVC is known for its stable physical properties, including high impact strength and resistance to grease, oil and other chemicals. As such, it has strong utility in rigid packaging applications including blister packs and clamshells; and flexible packaging uses such as bags for bedding and medical supplies, and wrapping for deli products and meat. Common products made from its recycled content include flooring, gutters, fences, traffic cones and loose-leaf binders.

Similar utility is found in the resin code four material, LDPE, which is known for its toughness and flexibility, and resin code five, PP, a critical component of flexible and rigid packaging. LDPE is used in packaging applications for frozen food and bags for fresh produce and newspapers. PP is found in containers for yogurt, takeout meals and deli foods. Recycling uses for LDPE cover a broad range, from shipping envelopes to garbage can liners and outdoor furniture. PP has strong recycling value in automotive applications such as battery cases and cables as well as signal applications.

Resin code six, general purpose polystyrene, is clear and hard and has a relatively low melting point. Typical applications include protective packaging, bottles and food containers. When recycled, it is used in protective packaging as well as food service applications such as foam egg cartons, among other uses.

Lastly, category seven in the RIC system indicates that the manufactured article is made with a resin other than the six previously specified or is made from more than one resin in a multilayer combination.

This article appears in the issue of Standardization News.